Plasma Thromboplastin Antecedent (PTA) Deficiency

Plasma thromboplastin antecedent (PTA) deficiency was first described by R. L. Rosenthal et al., in 1953,¹ as a mild to moderately severe hereditary hemorrhagic disease resembling hemophilia but occurring in both males and females. Further studies by the same group revealed fairly well-defined distinctions between antihemophilic globulin (AHG), plasma thromboplastin component (PTC), and PTA.² Only a few subsequent cases of PTA deficiency have been reported.^3,4 The present report deals with a family in which a coagulation disorder, eventually diagnosed as PTA deficiency, was found.* Both males and females were affected, inheritance taking place either through males or females. Of the 10 members of the family available for study, 5 showed indications of the disease (Fig. 1). However, the variability in laboratory tests indicated a somewhat less well-defined character of the deficient factor than is found in either the AHG or the PTC coagulation defect. In the case